1、BRITISH STANDARDBS EN14623:2005Devices to prevent pollution by backflow of potable water Air gaps with minimum circular overflow (verified by test or measurement) Family A, type GThe European Standard EN 14623:2005 has the status of a British StandardICS 13.060.20; 91.140.60g49g50g3g38g50g51g60g44g4
2、9g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58Licensed Copy: Wang Bin, na, Mon Apr 17 08:24:28 BST 2006, Uncontrolled Copy, (c) BSIBS EN 14623:2005This British Standard wa
3、s published under the authority of the Standards Policy and Strategy Committee on 26 January 2006 BSI 26 January 2006ISBN 0 580 47620 0National forewordThis British Standard is the official English language version of EN 14623:2005. It supersedes BS 6281-2:1982 which is withdrawn. The UK participati
4、on in its preparation was entrusted by Technical Committee B/504, Water supply, to Subcommittee B/504/14, Backflow prevention, which has the responsibility to: A list of organizations represented on this subcommittee can be obtained on request to its secretary.Cross-referencesThe British Standards w
5、hich implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.This public
6、ation does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible internationa
7、l/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK.Summary of pagesThis document comprises a front cover, an inside front cover, the EN title page, pa
8、ges 2 to 10, an inside back cover and a back cover.The BSI copyright notice displayed in this document indicates when the document was last issued.Amendments issued since publicationAmd. No. Date CommentsLicensed Copy: Wang Bin, na, Mon Apr 17 08:24:28 BST 2006, Uncontrolled Copy, (c) BSIEUROPEAN ST
9、ANDARDNORME EUROPENNEEUROPISCHE NORMEN 14623May 2005ICS 13.060.20; 91.140.60English versionDevices to prevent pollution by backflow of potable water - Airgaps with minimum circular overflow (verified by test ormeasurement) - Family A, type GDispositifs de protection contre la pollution de leau potab
10、lepar retour - Surverse avec trop plein (dfinie par essai dedpression) - Famille A, type GSicherungseinrichtungen zum Schutz des Trinkwassersgegen Verschmutzung durch Rckflieen - Freier Auslaufmit kreisfrmigem berlauf mit Mindestdurchmesser(Nachweis durch Prfung oder Messung) - Familie A, Typ GThis
11、European Standard was approved by CEN on 25 March 2005.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references c
12、oncerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own
13、 language and notified to the Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg,
14、 Malta, Netherlands, Norway, Poland, Portugal, Slovakia,Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2005 CEN All rights of exploitation
15、 in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 14623:2005: ELicensed Copy: Wang Bin, na, Mon Apr 17 08:24:28 BST 2006, Uncontrolled Copy, (c) BSIEN 14623:2005 (E) 2 Contents Page Foreword 3 Introduction4 1 Scope .5 2 Normative references .5 3 Terms and definitio
16、ns.5 4 Designation .6 5 Symbolization7 6 Materials 7 7 Requirements 7 8 Marking (not required for site constructed products)10 9 Technical documents .10 Licensed Copy: Wang Bin, na, Mon Apr 17 08:24:28 BST 2006, Uncontrolled Copy, (c) BSIEN 14623:2005 (E) 3 Foreword This European Standard (EN 14623:
17、2005) has been prepared by Technical Committee CEN/TC 164 “Water supply“, the secretariat of which is held by AFNOR. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by November 2005, and conflicting
18、national standards shall be withdrawn at the latest by November 2005. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland,
19、 France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. Licensed Copy: Wang Bin, na, Mon Apr 17 08:24:28 BST 2006, Uncontrolled Copy, (c) BSIEN 14623:20
20、05 (E) 4 Introduction In respect of potential adverse effects on the quality of water intended for human consumption, caused by the product covered by this European Standard: a) this European Standard provides no information as to whether the produce may be used without restriction in any of the Mem
21、ber state of the EU or EFTA; b) it should be noted that, while awaiting the adoption of verifiable European criteria, existing national regulations concerning the use and/or the characteristics of this product remain in force. Licensed Copy: Wang Bin, na, Mon Apr 17 08:24:28 BST 2006, Uncontrolled C
22、opy, (c) BSIEN 14623:2005 (E) 5 1 Scope This European Standard specifies the characteristics and the requirements of air gaps with overflow, family A, type G for nominal flow velocity not exceeding 3 m/s. Air gaps are devices for protection of potable water in water installations from pollution. Thi
23、s European Standard applies to air gaps in factory assembled products and to constructed air gaps in situ, and defines the physicochemical characteristics of materials of construction used for the purpose and application to ensure compliance with this document during normal working use. 2 Normative
24、references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 1717:2000, Protection against pollu
25、tion of potable water in water installations and general requirements of devices to prevent pollution by backflow. 3 Terms and definitions For the purposes of this European Standard, the terms and definitions of EN 1717:2000 and the following apply. 3.1 air gap with overflow family A, type G permane
26、nt and vertical distance between the lowest point of the feed orifice and the critical water level having an overflow capable of draining the maximum inflow of water under fault condition NOTE See Figure 1 for the design principle. Figure 1 Design principle 3.2 spillover level level at which water w
27、ill start to overflow the receiving vessel with all outlets closed 3.3 critical water level physical or piezometric level of liquid reached in any part of the appliance 2 s after closing the water inlet starting from the maximum fault level 3.4 dimension h height between the spillover level and the
28、critical level 3.5 maximum operational level in an open system the level that will be reached in normal operation (as defined by the manufacturer) Licensed Copy: Wang Bin, na, Mon Apr 17 08:24:28 BST 2006, Uncontrolled Copy, (c) BSIEN 14623:2005 (E) 6 3.6 maximum level highest water level H reached
29、above the spillover level under positive pressure fault condition with all outlets closed 3.7 splashing (requirements for protection) when maintaining the maximum flow rate at the maximum level if a contact is observed between the upstream component and the liquid in the receiving vessel due to spla
30、shing, foaming or turbulence, the air gap shall be increased to a point where no contact is observed 3.8 diameter of feed pipe (Bore D) diameter D is the maximum internal diameter within the last metre of the supply pipe or the DN of the inlet connection 4 Designation An air gap with overflow family
31、 A, type G is designated by: name; reference to this European Standard; denomination (see 3.8 DN or D); family and type. Example for a designation of an air gap with minimum circular overflow (verified by test or measurement) Family A (A), type G (G), DN 15 Air gap, EN 14623, Family A, Type G, DN 15
32、 Licensed Copy: Wang Bin, na, Mon Apr 17 08:24:28 BST 2006, Uncontrolled Copy, (c) BSIEN 14623:2005 (E) 7 5 Symbolization Figure 2 Graphic symbol 6 Materials The manufacturer shall state the type of materials chosen in his technical and commercial documents. The materials used in water installations
33、, including the materials of protection units in contact with drinking water, shall satisfy the European standards and national acceptance criteria and/or national restrictions for use currently in force in EU and EFTA. They shall be compatible with each other, with the water supplied and with the f
34、luids or substances that can come into contact with them. There are no special requirements concerning the materials downstream of the atmospheric outlet opening provided they do not have any harmful effect on the upstream part. 7 Requirements 7.1 General The protection assembly comprises four parts
35、: water inlet device; receiving vessel (container); overflow; air break to drain. 7.2 Water inlet device Every feed pipe, float-operated valve or other device which controls the inflow of water to a receiving vessel shall be securely and rigidly fixed to maintain air gap. The outlet of the inlet dev
36、ice shall not come into contact in any way with a product from downstream, and will always be above the maximum level H (see Figure 3). Adjustable or dismantleable joints are not permitted below the maximum operational level. Submerged supply pipes shall be made from corrosion resistant materials an
37、d be pressure tested as part of the inlet device. Licensed Copy: Wang Bin, na, Mon Apr 17 08:24:28 BST 2006, Uncontrolled Copy, (c) BSIEN 14623:2005 (E) 8 Key 1 Feed pipe 2 Feed orifice 3 Receiving vessel 4 Spillover level 5 Critical level (distance h) 6 Overflow pipe A Air gap (distance) D Internal
38、 diameter of feed pipe (bore) H Maximum level Figure 3 Air gaps with minimum circular overflow (verified by test or measurement) family A, type G 7.3 Overflow arrangements The overflow arrangements shall not be less than 19 mm internal diameter. The overflow arrangements shall include an air break p
39、rior to any connection to a drain. An air break to drain shall comply with the requirements of EN 1717, excluding W.Cs. 7.4 Air gap distance 7.4.1 Single supply For air gaps family A, type G the critical water level (h) shall be established and the air gap distance A measured from the lowest point o
40、f the water inlet to the critical water level (see Figure 3). For air gap distances see Table 1. The air gap can be determined by one of the following methods: a) h is determined by test measurement of the depth of water above the spillover level of the overflow 2 s after the inflow equal to Q = 0,1
41、4 D2in l/min has stopped or, a dynamic pressure of 1 MPa (10 bar) has stopped if the flow rate Q cannot be achieved. Where D is the inlet bore (see 3.8) and with all outlets (except the Licensed Copy: Wang Bin, na, Mon Apr 17 08:24:28 BST 2006, Uncontrolled Copy, (c) BSIEN 14623:2005 (E) 9 overflow)
42、 closed, based on a velocity of 3 m/s, or the maximum recommended flow rate for manufactured appliances when the flow rate is higher than Q; b) in the case of a pipe or valve not greater in size than 15 mm (G), by measurement of the air gap distance A from the lowest point of the feed orifice and th
43、e centre line of the overflow pipe. Table 1 Air gap distance Pipe/valve size (inch/metric) Distance A (mm) DN 15 (G ) 20 mm DN 20 (G ) 25 mm DN 22 (G ) 2 D 7.4.2 Multiple supplies In the case of multiple feed pipes to a single vessel having an overflow, the distance of the air gaps for the potable w
44、ater supply shall be dimension A above the critical water level. The critical water level (3.3) shall be determined with all feed pipes discharging at an individual inflow calculated at Q = 0,14 D2. If the flow rate Q cannot be achieved, apply a dynamic pressure of 1 MPa (10 bar) on all inlets. No f
45、eed orifice shall be less than distance A above the critical water level. For calculating air gap distance A use =22 DA 7.4.3 Backflow/back pressure If the receiving vessel can be subject to positive pressure backflow, it is important that the inlet orifice is positioned so that it cannot be contami
46、nated by the ascending/returning backflow fluid. When the air gap is part of an installation which can generate positive pressure backflow it is essential that a means of limiting the flow rate to a rate which will not comprise the overflow arrangement is incorporated, i.e. non return valve fitted u
47、pstream of the pressurisation unit. Potable water inlets shall terminate at a higher level than non-potable inlets and never closer than 2 D measured horizontally and vertically downward. 7.5 Verification 7.5.1 General Verification can be achieved by test or by measurement. 7.5.2 Procedure for verif
48、ication by test See 7.4.1 (a) and 7.4.2. a) Sequence of test close all outlets (except the overflow); identify D; calculate Q; apply flow rate Q and maintain maximum water level; note contact with the outlet of the inlet device(s) during filling and the maximum level; Licensed Copy: Wang Bin, na, Mo
49、n Apr 17 08:24:28 BST 2006, Uncontrolled Copy, (c) BSIEN 14623:2005 (E) 10 stop flow rate Q; after 2 s establish distance h; measure air gap between distance h and lowest point of the feed orifice. b) Requirements: no contact between the receiving vessel fluid and the outlet of the inlet device(s); measured air gap shall meet the requirements of dimension A (see Table 1). 7.5.3 Procedure for verification by measurement (single supply only) a) Sequence of measurement see 7.4.1 (b). b)
